As good as English curry is it would be terrible if you just pour it over the rice and leave it to soak in a bentou box.
Now, if you have one of those tiffin stacks instead...
I suppose a juubako might also work, but that is usually used only for fancy meals.
(Personally, I don't think Japanese 'curry" qualifies as curry at all, despite how good it can taste. More like curry-flavored meat and vegetables stew.)
Well, the early Japanese curry recipes were pretty much taken verbatim from English recipe books. (such as Mrs. Beeton's). It's changed a fair bit in the century since then, though... And I have had properly spicy Japanese curry. (Not to say, south Indian standards, but what is?)
It's more that the UK switched from 'British' to 'Indian' curry, and Japan stayed with 'British' turning it into 'Japanese'.
You could make a dam curry in a bento; that would work, if the box was big enough.
